Non-slipping tread-plug.



J. L. (LMPBBLLi NONSLIPPING THEM; PLUG. APPLICATION FILED JULY 18,1906.

958,363. ,Patenteamay 17,1910.

ulfflllll WITNESSES. MVr-moa wggy` jaw@ l UNITED STATES PATENT OFFICE.

JAMES L. CAMPBELL, OF LOWELL, MASSACHUSETTS, ASSIGNOR TO AMERICAN MASON SAFETY TREAD COMPANY, OF SACO, MAINE, A CORPORATION OF MAINE.

NON-SLIPPING TREAD-PLUG.

Specification of Letters Patent.

Patented May 17, 1910.

To all whom it may concern:

Be it known that I, JAMES L. CAMPBELL, a citizen of the United States, residing at Lowell, in the county of Middlesex and Commonwealth of Massachusetts, have invented a certain new and useful Improvement in Non-Slipping Tread-Plugs, of which the following is a specication. v

This invention relates to non-slipping tread-plugs and comprises ,means of retaining such plugs in treads where non-slipping plugs are especially necessary and where jar, vibration or spring, of the treads has a tendency to loosen said plugs, as in the footboards or running-boards of open streetcars, in the treads of temporary or slightly made wooden steps or stairs or where no risers are used, as step-ladders and ships ladders, or in gang-planks or similar comparatively thin and springy walks.

In the accompanying drawing, Figure l, is a side elevation of a part of an open streetcar, showing seats, sill and foot-board with my invention applied to said foot-board; Fig. 2, a plan of said foot-board provided with safety-plugs; Fig. 3, a section of a y tread as a part of a foot-board, with a plug in side elevation; Fig. 4:, a plan of the plug shown in Fig. 3; Figs. 5 and 6, central sections of plugs in treads, showing the attaching means in side elevation; Fig. 7 a horizontal section of a plug onthe line 7 7 in Fig. 8; Fig. 8, a vertical section on the line 8 8 in Fig. 7 the case represented in Figs. 3-6 being omitted in Figs. 7 and 8, which also show a modification of the attaching means.

A denotes a floor-sill of an open streetcar; B, the seats of the same; C, a foot-board or running-board, all of any usual construction. The foot-board being of wood and frequently slippery, endangers the safety of the conductor who walks thereon to collect his fares, and of the passengers who get on and oif the car and who sometimes are obliged to stand on said board. It has not been considered practicable to use upon the foot-board the metallic safety-treads having grooves lled with anti-slipping material commonly used on the steps of large buildings, owing to the great weight of said safety-treads and the diiiiculty of securing them in place and of retaining the lling in the grooves, because of the jar, vibration and spring of said foot-boards. It is dangerous to provide such foot-boards with non-slipping plugs or similar devices arranged at intervals from eachotherv and projecting to any considerable degree above the surface of the foot-board because such plugs would cause the conductor and passengers to stumble by engaging the'toes and heels of their shoes. There are .many other. situations where owing to the lightness of construction of the treads or their supports, heavy grooved and lled metallic plates cannot well be used. s

The safety plugs herein described are intended to supply the' place of safety-treads in all such cases. The safety-plug is represented (Figs. 3-6) as comprising preferably a short cylindrical hollow case D of metal, as sheet-iron or sheet-brass 0r tinplate, closed at its lower end CZ; a bolt E or E1 forming the shank of the plug passed down through the bottom d of said case until the head e e1 rests on the top of said bottom, a nut F to engage the threaded lower end e2 of said bolt or screw, a washer G, which may however be omitted and a suitable iilling I-I of cement or similar composition containing a gritty non-slipping substance, as finely divided carborundum or quartz or sand or any usual mixture of these, such that when the cement is set or hardened its surface will be rough and abrasive to engage the soles and heels of shoes. The cement lling should be slightly convex as shown. Lead or other non-slipping material may be used as a filling.

The foot-board or other similar tread is bored out at c to receive the plug with the top of the case D just flush with the top of the tread so that the convex top of the illing rises slightly above the tread surface or top of said tread, and a smaller hole c1 is bored entirely through said tread for the shank-screw or bolt which is of sufhcient length to reach below said tread, and to engage the nut F, as shown, to prevent the loosening of the safety-plug and to enable ythe plug to be tightened if it should become loose by shrinking of the wood of the tread or otherwise.

In Figs. 7 and 8, the case is omitted and the bolt or shank E2 is provided with a head c2 and an annular shoulder c3 or en-v largement of the shank which reaches to the bottom of the cement or non-slippin body of the plug while the head e2 is embe ded in said cement between the top and bottom thereof, said cement entirely covering and coming in contact with all parts of said head. Said head e2 may be a round disk as indicated by the dotted circle shown in Fig. 7, but preferably consists of arms or projections c* radial to the axis of the shank to enable the cement and the shank better to engage each other and to allow the upper and lower parts of the cement to be more perfectly united. In other respects the form of plug shown in Figs. 7 and 8 is the same as the plugshown in Figs. 345.

Preferably the plugs will be molded or completed in the factory but either form of plug may be filled in the tread, the case D of the plug first described being placed in the tread with its shank projecting through said tread and then filled, while in the plug last-named the counterbore or large hole serves as the mold for the non-slipping cement or material7 the shank being first passed through the tread and the body of the plug being cast around it by lling said counterbore with said cement.

I claim as my invention l. A non-slipping tread-plug comprising a suitable body of cement containing gritty material adapted to be let into a tread flush with the tread surface thereof, and an attaching shank rigidly secured to said body and adapted to extend through said tread, and means to engage said shank below said tread and to retain the same in said tread.

2. A non-slipping tread-plug consisting of a suitable casefilled with non-slipping material, said case being adapted to be let into a tread and having a screw-threaded shank rigidly connected to said case and adapted to extend through said tread and a nut to engage said shank below said tread.

In witness whereof, I have affixed my signature, in presence of two Witnesses.

JAMES L. CAMPBELL.

IVitnesses:

ALBERT M. MOORE, VILLIAM S. LAMsoN. 

